Chicago to Memphis - Offbeat Suggestions?

Folks - heading to find Elvis. Graceland. The Blues. Lots of BBQ. Fun and sun! July 4th weekend (driving from Chicago to Memphis, Friday to Tuesday).

I have all of the usual places to visit in Memphis so I was looking for suggestions on "offbeat" side trips along the way - or down there. Largest ball of wax paper, world's largest pez collection - that kind of stuff. Maybe even some serious things...who knows.